Scientists using the newly sequenced genome of the coffee plant revealed that the caffeine found in coffee is an independent genetic trait and are not linked to the caffeine in chocolate or tea.
“It’s an accident that has been frozen in place very likely by the influence of natural selection,” says University of Buffalo evolutionary biologist Victor Albert. He and more than 60 other researchers from around the world mapped out the genetic information of the chief agricultural product of many tropical countries.
Researchers from the University of Barcelona (UB) and the Biodiversity Research Institute of the University of Barcelona (IRBio) have participated in an international consortium which has newly sequenced the genome of the coffee plant Coffea canephora, also known as the Robusta variety, that account to 30 percent of the world’s coffee produced. It is second in importance to Arabica, generally known for its less strong, smoother taste.
University of North Carolina plant genomics professor Jeff Dangl, who wasn’t part of the study, notes “natural selection to help coffee plants deter insects turned out so well for us.” But he adds, “Unfortunately, coffee is now under epidemic attack by pathogens that are not deterred by caffeine, and we need all the clever genetics and genomics to save it.”
“For any agricultural plant, having a genome is a prerequisite for any sort of high technology breeding or molecular modification. Without a genome, we couldn’t do any real advanced research on coffee that would allow us to improve it — not in this day and age,” said Albert.
“Coffee is as important to everyday early risers as it is to the global economy. Accordingly, a genome sequence could be a significant step toward improving coffee,” said Philippe Lashermes, a researcher at the French Institute of Research for Development (IRD). “By looking at the coffee genome and genes specific to coffee, we were able to draw some conclusions about what makes coffee special.”
The principal authors of the study are Lashermes, along with Patrick Wincker and France Denoeud, genome scientists at the French National Sequencing Center (CEA-Genoscope), and Victor Albert.
Julio Rozas, professor from the Department of Genetics of the Faculty of Biology at UB and ICREA Academia researcher, and Pablo Lirando, UB postdoctoral researcher, were also the part of the analysis of coffee DNA.
More than 2.25 billion cups of coffee are consumed everyday around the globe and 8.7 million tons were produced just last year, according to an estimate from the International Coffee Organization.
Along with its the popular beverage’s aroma and the bitterness of beans, caffeine undoubtedly is a big part of its appeal and the coffee plant possess around 25,500 genes responsible for different proteins, that relate to the production of alkaloid and flavonoid compounds.
The genes responsible for coffee’s caffeine-production code for a group of enzymes called N-methyltransferases.
“If you were to look at the family tree of N-methyltransferases, you would find that the genes responsible for caffeine synthesis in coffee have evolved along an entirely separate branch from those in charge of caffeine synthesis in chocolate,” says Albert. You might find enzymes in chocolate that are closely related to the caffeine-producing enzymes in coffee, he explains, but they would have nothing to do with chocolate’s caffeine-producing enzymes. Both plants rely on N-methyltransferases to generate caffeine, but they took different evolutionary routes to do so. It’s a classic example of what evolutionary biologists call “convergent evolution.”
Coffee plants utilised the caffeine to lure pollinators and restrained herbivorous insects from preying on the plant’s leaves.
Albert and his colleagues have high hopes for the useful application of the sequencing. “When we compared the coffee to several other species, we saw a huge enrichment in disease-resistant genes,” he said. “Those can now be rapidly explored in more detail, and could be of use in both coffee breeding and in the molecular modification of coffee.”
The study, was published online in the journal Science Thursday.